TP53 and leukemia: A pair of recent studies using large cohorts of individuals with clonal hematopoiesis to attempt to define the factors that associate with progression to leukemia identified that in addition to TP53 mutations, spliceosomal mutations were associated with high risk of progression to AML.39, 40 These studies suggest that spliceosomal mutations are among the first mutations to occur in hematopoietic stem cells and because of their very high risk association with leukemia may be disease‐initiating mutations.